Recently, as the research and development of next-generation displays is actively being pursued, a variety of display means is being introduced. A typical example of the next-generation displays may include an electronic ink. The electronic ink is a display in which an electric field is applied to particles of specific colors (e.g., black and white) respectively having negative charges and positive charges to display the specific colors. Electronic ink has the advantages of low power consumption and flexible display. However, the electronic ink is limited because it is difficult to represent various colors since the color of the particles is set to specific colors. Electronic ink has the further limitation of being unsuitable for displaying moving images because the display switching speed is low.
To fundamentally overcome the aforementioned problems of the conventional next-generation display, various methods have been suggested such as a method using the principle of photonic crystal.
The term “photonic crystal” refers to a material or crystal that is rendered in a color corresponding to a specific range of wavelengths by reflecting only light of a particular wavelength range among lights incident on a regularly arranged microstructure and transmitting light of the other wavelength ranges. Typical examples of photonic crystals include butterfly wings, beetle shells, etc. Although they do not contain any pigment, they include a unique photonic crystal structure, so they can produce unique colors.
While photonic crystals existing in nature reflect only light of a particular wavelength, artificially synthesized photonic crystals can arbitrarily change the crystalline structure thereof (e.g., interlayer thickness of the photonic crystals) by various external stimuli. As a result, the wavelength range of reflected light can be freely adjusted to cover ultraviolet or infrared regions as well as visible light regions.
Focusing on this point, the present applicants have arrived at the present invention upon discovering that it is possible to implement a display method and display device using photonic crystal characteristics. An electric field is applied to particles having electric charges or electrical polarization characteristics and/or a solvent with electrical polarization characteristics to control inter-particle distances of the particles and thereby reflect light of a certain wavelength range from the particles.